Hydraulic clamp for paper cutters



y 1950 F. w. SEYBOLD 2,506,651

HYDRAULIC CLAMP FOR PAPER CUTTERS Filed March 1, 1946 3 Sheets-Sheet 1 (l O) l I N VEN TOR. FREDER/CK 14 SEVBOLD BY QM saw ATTORNEYS.

May 9, 1950 F. W. SEYBOLD HYDRAULIC CLAMP FOR PAPER CUTTERS *Filed March 1, 1946 INVENTOR. FEEDER/CK I44 SEVBOLD A TTORNEVS.

Patented May 9, 1950 HYDRAULIC CLAMP FOR PAPER CUTTERS Frederick W. Seybold, Westfield, N. J., assignor to E. P. Lawson 00., Inc., New York, N. Y., a

corporation of New York Application March 1, 1946, Serial N 0. 651,279

23 Claims. (01. 164-54) My present invention relates to paper cutting machines of the guillotine type and more particularly to hydraulic operating means for the clamping mechanism used in such machines.

In paper cutting machines wherein the knife is caused to descend downwardly and move at the same time laterally with respect to a paper pile on the work table, it has long been found necessary to provide clamping mechanism which contacts the paper pile just before the knife blade reaches it, squeezes the air out of the paper pile just behind the knife blade and holds the paper pile steady while the knife blade is going through. Since relatively great force, of the order of tons, must be exerted by the clamp, various mechanical as well as hydraulic force multiplying means have previously been suggested and in some cases used to clamp the paper.

Attempts have been made to drive the clamp through its entire stroke by hydraulic pressure derived from a pump. Owing, however, to the rapid action of the knife of a paper cutting machine hydraulic pressure thus derived driving the clamp through its entire stroke is both expensive in initial cost of equipment as well as in operation. In order to obtain force multiplication the stroke of the operating members inthe case of such prior hydraulic drives for the operation of the clamp must be over a length or angle many times that of the stroke of the clamp.

In other prior devices, hydraulic means have been utilized simply for power transmission to the clamp without force multiplication; the full pressure must then be developed in the driving mechanism.

A primary object of my invention is the ar rangement of clamp operating means in such manner that force multiplying hydraulic driving means are used over a relatively minute portion of the stroke; that is the force multiplying bydraulic means comes into operation only after the clamp has contacted the paper pile. The force multiplying hydraulic means is then operative to force the clamp tightly down on the paper pile.

Another and corollary object of my invention is the provision of combined driving means for the clamp of a paper cutter wherein the clamp is moved down mechanically into contact with the upper surface of the paper pile on the work table and after such contact has been made the force multiplying hydraulic means is brought into operation to force theclamp with great pressure against the paper pile. Since the hydraulically operated portion of the stroke is thus relatively minute, large forces may be developed on the 2 clamp even though the applied force is consider ably smaller.

The foregoing and many other objects of my invention will become apparent in the following description and drawings in which:

Figure 1 is a schematic view showing my novel clamp in a raised position.

Figure 2 is a schematic view showing my novel clamp brought down into contact with the paper prior to the application of hydraulic pressure thereto.

Figure 3 shows the clamp of Figures 1 and 2 with force multiplying hydraulic pressure applied to the clamp.

Figure 4 is a schematic side view of the clamp of Figures 1 to 3 taken from line 4-4 of Figure 1.

Figure 5 is a corresponding view taken from line 5-5 of Figure 2.

Figure 6 is a view of a slightly modified form of clamp operating device showing the raised position of the clamp.

Figure 7 is a schematic view showing the clamp lowered into contact with the paper stack.

Figure 8 is a schematic View showing the application of force multiplying hydraulic pressure to the clamp of Figures 6 and 7.

Referring now to Figures 1, 2 and 3, the clamp IE comprises a transverse bar or casting having the clamping surface II and is free to reciprocate vertically in guides schematically indicated at [2 and I3 in the frame of the paper cutter. The clamp ll] operates above the work table l5 of the paper cutter on which stacks of paper may be placed to be cut. The paper cutter also includes a knife blade not shown which is mounted just in front of the clamp Ill and is so arranged that it will come into contact with the paper immediately after the clamp has engaged the paper and compressed it. The knife blade and the knife operating mechanism is not shown since it constitutes no part of the present invention. However, it is understood that when a paper stack is placed on the work table and the paper cutter is tripped into operation, the surface I I of clamp I6 is brought down onto the paper stack on work table 5 and compresses it just before the knife edge enters the paper stack and the clamp is arranged to rise just after the knife edge on its withdrawal from the paper stack leaves the stack.

The clamp I0 is provided with a pair of opposite lateral extensions H, i 8 having the pins I9, 20 to which are attached the pull bars 2|, 22.

The lower end of pull bar 22 is connected to the pin 23 at the upper end of bell crank lever 24.

The lower end of pull bar 2| is connected to the pin at the upper end of cell crank lever 25. Bell crank levers 24', and 26 are pivoted on the studs 3!), 3E. The lower end of bell crank lever 24 is connected at the pin 33 to the link 34, the Opposite endof which is connected by pin 35 to the lug 35 of hydraulic piston 31.

The lower end of bell crank lever 25 is similarly connected by pin to link 4!, the opposite end of which is connected by pin 52 to the lug 43 of hydraulic piston M. a 1

Pin 33 on the lower end of hell-crank lever is r is also connected to the vertical link5i3 which is lower pin 52; The single link 53 is connected, I

approximately midway between pins 33 and 52, by the pin 53 to the link 55, theopposite end of which is connected by pin 55 to the driving crank 56.

The lower end of link 58 is connected by pin 52, to linkas, the oppositeend ofwhich is-connected bypin 58 to the piston rod 55, which carries the piston 52 rigidly secured. thereto. Pistonjrod 5! extends through piston 62 to the opposite side forming extension ft to; V Valve 65 is slidably mounted on extension Ma of the piston rod BI and is biased toward the left on this; extension by the" compression spring 61 captured between surface 68 of valve 65 and collar 69 secured at therightfhand end of extension 6m. Consequently, valve 65 is biased toward the left but after it hasreached its limit of movementto the left, as hereinafter: described, the

piston rod 6|, piston 52 and extension 61a of piston rod 6! may slide-Withrespect to the valve 55. Pistons-3! :and' 44 operate "horizontally in the horizontalcylinderl'fl. Fluid intake duct H and cylinder H1 communicates at'its lower endirwith the duct 12 connectedwith the fluid reservoir '13.

Valve 65 in the position shown in Figure 1 permits the free flow of fluid from reservoir 13 and duct" lip-through the intake duct-.1! into the cylinder 1G; 'Valve 65' is arrangedso that when it is moved from the position shown in Figure 1' to the position shown in Figure 2, it blocks the lower portion of fluid-intake duct H and thus seals the fluid, intake H of the cylinder 10 from thereservoir'13; For this purpose, asthe'rod 5i and piston 62 moves to the left-drawing, piston extension Bid and collarti) along, the valve'65 also moves to the left, across the duct ll until the end of valve '65 fits against theshoulder l6 at -theleft side-of duct 1 l thussealing and blocking off the lower portionof duct '1 I As the piston 62 "moves still further to the left to the position shown in Figure 3,-the piston rod 61 and its extension 6hr slide with respect "to the valvefiii which remains stationarythus compressing the spring 61. v I H Piston 82 operates in the I lower cylinder 88 which communicates-with the duct 8|, duct 8! communicatesthrough the check valvev 82 with the duct 83 which communicates with duct '3 I' at a. point above theublocking-valveifi5. I

Check valve 32 is arranged so. that it may open upwardly and is biased closednagainst the valve -ll''by compression'spring 86.. I V

Any additional 'check'valve 90 is provided at the lower end of 'ductill closing thepassage between duct 81 and duct 72. This valve is biased by its own weight downwardly against the seat 9! and is arranged that it may only open, in an upward direction; 7 H V v V 7 A discharge valve '95 is also provided being biased upwardly closed against its seat :96 by the compression spring illaround the-valve stem98 4 between the under-surface of valve and the adjusting knob 539.

In operation, a stack of paper ")0 is placed on the work table 15 and the paper cutting mechanism is tripped into operation. The crank 56 is rotated counterclockwise by the drive mechanism thus forcing the link '54 to the left, Link 54 forces the pivot '53 and hence link 50 to the left counterclockwise around the pivot 52, which is held stationary by means of abutment I ti on the frame of the machine, against which the collar 59 of extension 61a of piston rod 6 i rests. Counterclock'wise rotation of link 50 forces pin 33 to the left causing the bell crank lever 24 to rotate in a clockwise direction;

With the duct "H completely open and connecting reservoir 13 and duct 12 with the cylincler "Hi, the pistons 31 and 44 may readily follow the rotation of the bell crank levers 24 and 26. Rotation of bell crank lever 24 in a clockwise direction results in pulling down the pull bar 22 which thus pulls down the clamp I0.

Pull bar 2! accordingly moves'down with clamp it and causes the bell crank lever 26 to rotate in a counterclockwise direction also pulling out the piston it to the right. This downward mechanical movement of the clamp, Hi continues :until the surface I l of clamp ill) contacts the top of paper stack H370.

Pivot 33 now becomes stationary and cannot move since it is mechanically tied tothe paper clamp, the movement of which is now blocked by the upper surface of paper stack 10!).

Further rotation of crank 55 in a counterclock- Wise direction now, through link54 and pin 53, forces the lower end 52 oflink. 50 to rotate in a clockwise direction and forces the-'entire-link 59 to rotate about the ,pivot 33;

This now pulls ontlink 59 and piston rod 6| pulling the piston 62 to theileft. As the'piston rod 6! and piston fifiarepulled to the leftthe valve t5 moves from the non-blocking position of Figure 'l'to the position of Figure 2 where it blocks the communication from reservoir 13 and duct 72 through duct ll tocylinder Hi. Cylinder leis thus blocked off from reservoir '53.

The further movement of crank 55 in a counterclockwise direction now pulls the piston 62 further to the left as shown in Figure 3 forcing the fluid from the lower cylinder 80 up through the duct 8i liftingthe check Valve-85 and forcing the fluid through duct 83 and the upper portion of duct i! into cylinder 10. V

In the position of Figure 2, it will be seen that cylinder 8E), duct 8|, duct 83, the upper portion of duct ll and cylinder 70 are now a closed systern. Consequently, any movement of piston 52 to the left in the lower cylinder 8!) will cause a hydraulic transmission of power through the closed system to the pistons 31 and 4d. The power transmission will be a force multiplying transmission since piston 52 and lower cylinder Eii a'reof much smaller diameterthan pistons 31 and it in upper cylinderflfl. Consequently, the movement of piston '62 tothe left .afterfth'e position of Figure 2 has been reached and tothe position of Figurefi will result in forcing the pistons 53? and 46 outwardly with hydraulicallyv multiplied force. This will cause simultaneous additional clockwise rotation of bell crank" lever 24 and counterclockwise rotationof bell crank lever 25 pulling the pullbars'22 and 2i down at hydrau'lically multiplied force and thereby pulling the clamp It] down upon the top of stack 100 with hydraulically multipliedforce.

Valve 951s provided as a discharge, pressure regulating and safety valve; in the event that the piston 62 exerts too great a force on the pistons 31 and 44 of cylinder 10, it will be depressed and opened by this additional force to permit discharge of the excess liquid from cylinder through duct I03 to reservoir 13.

This is necessary because the piston 62 is so arranged that it will be forced to travel to the left to a much greater extent with a high stack than with a lower stack in order to permit the crank 56 to make a full revolution.

After the high stack is contacted and the hydraulic mechanism is thus brought into operation, the paper can be compressed only to a limited extent and further complete travel of piston 62 to the left will result in breaking some portion of the mechanism. Consequently, discharge valve 95 is adjusted by the hand knob 99 so that it will bleed off excess liquid under pressure after full compression of the paper stack has been obtained, thus permitting piston 62 to make its full movement to the left.

With a very low stack piston 62 will be brought into operation relatively very late in the first 180 of rotation of the crank 56 and discharge valve 95 may not be forced to operate.

However, my novel device thus provides a meth ed by which very high pressures are automaticall obtained in a high paper stack for which such high pressures are required and relatively lower pressures may be obtained for a low paper stack which does not require high pressures.

The device is so arranged as shown that the clamp is brought down rapidly mechanically and after it has contacted the paper stack, the hydraulic mechanism is brought into operation to provide adequate clamping pressure.

After the apparatus has reached the position of Figure 3 and the knife has gone through the stack, the continued counterclockwise movement of crank 56 through the remaining 180 of said movement first causes a counterclockwise rotation of link 53 around pivot 33 moving link 59 and piston rod 6! to the right. When piston 62 engages the surface E5 of valve 65 it also forces the valve 65 to the right thus opening the duct H and establishing communication between the reservoir it and cylinder 70 to equalize the pressure of cylinder 18 with the atmospheric pressure of reservoir 73. At the same time, and in order to permit piston 62 to move readily to the right, the check valve 98 is so arranged that on such return movement of piston 62 to the right it is raised and fluid may flow from reservoir 13 through duct 12 up into duct 81 and lower cylinder 89 to permit equalization of pressure.

After the collar 69 on extension cm of piston rod 8! has struck abutment l0] and further movement of piston 52 and the pivot 52 to the right is limited, then further rotation of crank 56 counterclockwise through the remainder of the return cycle will cause the link 50 to pivot clockwise around the pivot 52 driving the pivot 33 to the right and causing counterclockwise rotation of bell crank lever 24 thereby forcing up link 22 and pushing up the clamp ill.

Clamp it may, of course, be counter-balanced in any suitable well-known manner by appropriate springs so that the upward movement thereof is substantially aided by the springs.

ly occupy the full width of the machine and are usually placed against the left hand guide, this introduces a further possibility of canting.

For this reason in order to prevent canting of the clamp, a horizontal shaft H8 (see also Figures 4 and 5) is arranged in the rear of the clamp I 0 journalled in appropriate bearings III, III supported in any suitable manner by the frame of the entire mechanism.

Gear segments H2, H2 are attached to the opposite ends of shaft H0 and mesh with the racks I I3, H3 on the back of the clamp. The torsional stiffness of shaft ill] will, therefore, prevent canting or cocking of the clamp I 0 owing to the fact that force is exerted directly during mechanical movement on only one side of the clamp or owing to the placing of a very narrow pile against one side of the work table.

This latter consideration that a narrow pile may be placed against one side of the work table is of course the primary one as far as canting or cocking of the clamp is concerned since maximum force is exerted on the clamp ill only by the hydraulic pistons 3'5 and 44 which operate simultaneously on both sides of the clamp.

The reservoir 73 is provided with an appropri ate opening I20 through which additional fluid may be introduced into the system. The level of fluid in the reservoir 1'3 should always be just above the upper level of cylinder 10.

It will also be noted that in the system just shown in Figures 1, 2 and 3, the fluid is subject to pressure only in cylinders 80 and iii and in ducts 8i and 82 and a portion of duct H between them.

The fluid in reservoir 13 and ducts 12 and I03 is never under pressure so that no special sealing means is required for opening iZil other than any well known means for excluding dust and foreign matter and the opening I28 may readily be opened and inspected to determine that a proper fluid level is maintained.

By the means herein shown, therefore, I provide a simple, rapidly operated mechanical means for lowering the clamp Hi quickly into engagement with the upper surface of the paper stack I00. As soon as this engagement is reached and the movement of the clamp til further downwardly is blocked by the paper stack then the hydraulic mechanism is brought into operation to cause the clamp to squeeze the paper stack tight under force multiplying hydraulic pressure. Consequently, where the clamp is provided with a 6" working stroke and where a 3" pile of pa per is placed on the work table, the clamp is moved downwardly 3" mechanically to contact paper pile) force multiplying hydraulic means Since during the mechanical movement downmay be utilized for this purpose with a relatively very small volume of hydraulic fluid.

It will be obvious that my invention as described above is capable of many variations and modifications. Thus in Figures 6. 7 and 8, I have shown a slight variation of the hydraulic portion of the operating device.

In the case of Figures 6, 7 and. 8, the clamp ID, the mechanical means therefor and the means ascents: I

for preventing sam'isgahereor are :the t'sam'e: that shown in Figures 31 to "3-and have thus been given the same reference numbers -Similarly; thepistons 3l' and 44in the upper hydraulic cylinder IIl-operatein thevsame markner as in the case ofFigures :1 to 3 and have also been given-the same reference numbers;

' Also in Figuresfi, '7 and-8, the mechanical drive from crank 55 first causes =thelink fill-to pivot around pivot 52 and afterlthe downwardimovement of clamp- Iii-is mechanically stopped :by the paper pile, -the--link 5E! pivots around the upper plvot'33 to operate the hydraulicmechanism to move-'the'pistons fil -and Ml 'outwardly.

In the case of Figures 6, land 8, the hydraulic system is'modified: so that 'the'link I59 attached to the lower pivotz52 oflinkf 513 is connected'by pivot IEiito piston rod IM which-carries piston I62'rigidly secured thereon; 1 r I Valve I65 is slidably mounted'on piston rod I6I and is biased totheleft by compression'spring ISL captured between the-surface I758 of valve Hi5 and surface 5% of piston l62u Anadditional compression spring I36. is provided, captured between a collar I'3I on link I59 and a stationary portion I32 of the-frame of the'mechanism. through an 7 opening I33 of which link J59 passes. Piston I82 operates in the lower cylinder I30 andis cone nected by duct I83 to the-ductlll which communicates with the Iuppenc'ylinderlfl. r The left surface of'lower portion of-Iduct ITI .is provided with the valve seat lIBiin whichthe surface I75 of valve I55 may be seatedtotblockand seal the duct ill andth'us to break the. connection through duct Ill from'upper cylinder ID to lower duct numbered discharge valve .of Figures 1,12 andu3;

The-operation of this modification of my inven-. tion follows exactly the ioperationiof the preferred modification of Figures 1,.2and3;

The clamp I8 is first pulled down mechanically by movement to the left of link 54 .in-response to counterclockwise rotation of the driving crank 55.

This first causes'the link 50 to pivot counterclockwise on pivot 52 to rotate bell crank lever 24 clockwise to pull down the clamp II) When the clamp I3 contacts the paper pile; the further rotation of bell crank lever'24 clockwise'is blocked-.--

and piston I52 to the left and compressing spring- I3il. The compression spring I6! between piston I62 and valve I65 drives the valve I65Jto the left to seat against the shoulder or valve seat 115 in the duct III blocking ofi the duct III as shown in Figure '7 and closing the connection between the cylinder 19 and reservoir I3.

Further movement of link 50. clockwise and link I59 to the left pulling the pistonrod IGI to the left "now causes compression of spring 'Itl'as well as 'fur'ther; compression; 10f spring 5. I 30 and: pulls:

th'piston i 62 to the left irrthe' lower cylinder I891 Thexlower cylinder; I80; duct] 83,-: the :upper portion of duct III"and cylinder lllarenow.a closed hydrauli'c'systemi: I r

The relative smallness ofthe diameter of piston 7 I62 with respect to the diameter of pistons 31 and 44 now produces a'force multiplying effect.

As piston I621is'thus pulled further to the left,

the fluid is compressedintductsI83 and Ill and in cylinder Ill forcing the pistons '33 and dd out wardly under force multiplying pressure. This provides force multiplying :hydraulicflmeans for squeezing the clampdown with increased pressure on the paper pile as previouslydescribed.

In the event that the-movement of piston I62 too far to the left raises the pressure in cylinder Ill beyond the safetylimit, the excess liquid may bleed off through the discharge valve 95 as previously described. After'the crank 55 has reached: the position shown in Figure 8, further rotation" V will permit the piston rod I6I and link IEQ'tou move to the right under the influence of compression spring I39. The discharge valve 95 will close,

if. it has already been,opened,-. and a volume of fluid will be confined-in the cylinder T0, the upper portion of duct IIl, duct I83 and cylinder I89" Consequently, as the piston I62 now moves to the right the pistons 3'1 and d4 will move inwardly releasing thehydraulic pressure on the clamp because the volume of cylinder I86 will increase owing to the motion tothe right of the pressure piston IE2.

Thus the hydraulic pressure will be quickly released during thereturn stroke of crank 53.

On completion of the movement to the right of piston I62, the valve I65 moves to the right andopens the duct I'll establishing communication from cylinder I0 through ducts Ill and I72 to the reservoir I3.

The completion of the counterclockwise rotae tion of the crank 55 back to the position of Figure 6 will nowcause the link 50 to pivot clockwise around pivot 52 rotating bell crank lever 2 counterclockwise and lifting the clamp It.

In this modified form also it will be seen that the clamp Ill is moved downwardly to contact the upper surface of the paper pile with a rapid mechanical movement of relatively low power and is then squeezed down the remaining fraction of an inch necessary to compress the paper pile by force multiplying hydraulic means; 7

My invention thus reduces the amount of power required. Themechanical force required to move the clamp down need be only slightly greater than that necessary to overcome the counter-balancing means to maintain the clamp in raised position, 7

When the clamp contacts the pile, the drive means is then effective to squeeze the clamp down hard on the paper pile to compress the samewith several tonsof pressure owing to fact that when the paper pile is contacted, force tates clockwise aroundthe pivot This pulls the link I59 to the left pulling the piston rod I61 multiplying vhydraulic means is introduced be tween thedrive and the pull bar of the clamp.

It is no longer necessary todevelop the full clamping pressure in the driving mechanism and the use of such force multiplying hydraulic means makes it possible to incorporate much less construction. This is so because long ducts and long strokes or long angles of movement of the driving means become unnecessary. Even with a high pile of relatively soft and pulpy paper the amount of movement required for the clamp to compress the paper pile after the clamp has first contacted the paper pile may be of the order of and less.

The developed pressure in the cylinder it is proportional to the area of the pistons 31 and 44 and the pressure piston 62. For example, if the pistons 31 and 44 are 6 inches in diameter and the pressure piston 62 and the piston rod (ii are respectively 3" and 1 in diameter, then the combined pressure on the bell cranks 24 and 26 is 9 times greater than the pressure exerted on the liquid by piston 62.

By means of the foregoing, therefore, I have provided a novel hydraulic operating means for the clamp of a paper cutter wherein the clamp is brought down mechanically in any suitable manner into engagement with the upper surface of the paper stack and after it has contacted the upper surface of the paper stack is then forced down by force multiplying hydraulic means to compress the stack with great pressure.

In the foregoing, I have described my invention solely in connection with illustrative embodiments thereof. Since many variations and modifications of my invention will now be obvious to those skilled in the art, I prefer to be bound not by the specific disclosures herein contained but only by the appended claims.

I claim:

1. In combination, a clamp for operating on material, a support for said material, a source of driving power a first drive connecting from said source of power to said clamp, a second drive connection from said source of power to said clamp, means whereby said second connection is ineffective while said first connection transfers driving power from said source to operate said clamp, and means whereby after said first drive connection has effected a predetermined operation on said clamp, said second drive connection becomes effective to transfer driving power from said source to further operate said clamp.

2. In combination, a clamp for operating on material, a support for said material, a source of driving power, a first drive connecting from said source of power to said clamp, a second drive connection from said source of power to said clamp, means whereby said second connection is ineffective while said first connection transfers drivin power from said source to operate said clamp, and means whereby after said first drive connection has effected a predetermined operation on said clamp, said second drive connection becomes effective to transfer driving power from said source to further operate said clamp, the force multiplication of said second drive connection being greater than said first drive connection.

3. In combination, a clamp for operating on material, a support for said material, a source of driving power, means for connecting said source to said clamp for operating said clamp to compress said material, and additional connections between the source of power and the clamp for increasing the force multiplication of said connecting means to increase the force applied to said'material from said source, said additional connections being operative in response to the engagement of the clamp with the material.

'4. In combination, an operating member for clamping material, a support for said material, a source of driving power, means for connecting said source to said operating member for applying clamping force on said material, and additional connections between the source of power and the clamp for increasing the force multiplication of said connecting means to increase the force applied to said material from said source; said additional connections being operative in response to the engagement of the clamp with the material and in proportion to the resistance encountered by the clamp in engaging the material.

5. A clamp for compressing a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack.

6. A clamp for comprising a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack after said clamp has come into engagement with said paper stack.

7. A clamp for compressing a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp relatively rapidly into contact with said paper stack; and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack.

8. A clamp for compressing a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp relatively rapidly into contact with said paper stack; and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack after said clamp has come into engagement with said paper stack.

9. A clamp for compressing a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and additional force multiplying hydraulic connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack; said additional connections being operative in response to the engagement of the clamp with the material and in proportion to the resistance encountered by the clamp in engaging the material.

10. A clamp for compressing a paper stack; a support for said paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set'of connections from said 'pa-pe'r stac V relatively short stroke hydraulicconnections be:

trim-said 5a ii I cl'an r'p opea'ble' t'o move shid pi'dI-y' i into contact with: said and add-itienal force" multiplying twen sid Cirii'i ifiealiS- and-said'eiampror forcirfigsaid clamp into high-'{pres'sur'e "engagement drive'means; a'fi'r'st set 'of'connections from said 'diive'rneans to said clamp operable to' move said r'elatively fapidly into contactwith said paper stack; and additional force multiplying feIa-tively' s hort stroke"nydrauuesonnections. betvv en'said dr'iv' niean'safidsaid'clamp for forc- 1 g aid clam intofhigl'i pi's'sure'iengagement aitrsaid'clamp has come into gagmei'it iifitfi Said paper stack.

' 1'2f-A-jclanid'for'etimpiessing a paper stack; part for said t per tack; said clamp being 'fiiovakil toward 'away'rrorri Said paper-stack; drive means a fir'st set of eormeetio'ns from said drive means to said clamp operable td rnove said la fnp i el atively rfiidfi iiit intat With Said paper stasis; V and additional' force multiplying R e fiyfifailii dnfition'sbe 'aiiiisaid amp for rare- 9411613)" iiitfi hih 5 pressure engagement mg ski-id. cl

msvabietsw rd an away from said paperstacki srive'means ror; sa ame; a -connecting 11111;,

one end" offs'aid link being -'ennected tested iiisaidi'ver hih'g some tea to tn cthe'r' end of said link; theseean "ens ersaid lever being 'means;'-operatin or'said to rotate said'leverto matically s h'epteafbet nsaia dnve meaiis and said lever when the alarms engages the aper stack-- r a i l. in a paper imachine a' table; for supporting a paper stack to beast; a clamp for (im ressing the aper Sttli; said clamp bifig movable toward slides-a3; fro'in sa id paper stack;

drive means for said clamp; said'clamp having a pull bar a pivotall yfnoiinted lever; the first end of'sa id lever being connected to said pull multiplying connecting means; the driven-side of said 7 force multiplyingconnecting means beingconnected't thesecond end oisaid lever;

said drive means being connected to saidlinh between the ends thereof said operating means moving "said link about-the'pivot on its said opposite end to rotate said leverand move the clamp intoengagementwith the paper stack; said drive means thereafter moving the :oppositeend of said about the pivot at first mentioned end; to actuate asaid force multiplying means th bar; a link said aciamri mte nessurer engagement with said paperstaclz.

l 15. 1 K. paper cutting: machine -:.a 'ta'bleior support-5i 1 gr a paperristack' to' b'e' cut far-clamp for compressing the paper stack; said: clamp: vbeing niovable toward and aiway'ir'om said -paper stack;

drive nieans for said: elainpy saaid clamp: having a pull bar; a pivotally mounted leveri the" first end of: said-lever being? connected." to said-pull pivetalliy connected at one i end to the second end of saidilever'y-iorce multiplying l'iydraul ic conheeting' meanathe opposite end of said being connected to theidriving siderof said ice :multipliv hydraulic connecting -ineans; the driven 1 de ef said force multiplying hydramic connecting neansrbeing c'onnected to the second end of said lev ert saidiclrive means being-connected to s'aid- Iinh hetween the ends thereof; said operating means moving said link about the pivot on its/said opposite end to rotate said levei and rnove the clamp into engagement with the paper stack; said drive means thereafter inoving the opposite end oi -said link about the pivot-at first; mentioned end to actuate said forcemulti-piying hydraulie means to move said clamp into pressure:engagement?withr saidzpaper stack.

16. In a paper cutting machine a't'able iorisupporting a paper stacktebe'eut; a, clamp for cornpressing" the paper stackp saidiciamp being movable toward andaW'a-y -fi0in: said -paper stack; drivemeans rorsai clamp; said clam having a pull bar?a pivotally rifountedlever; the first end of said lever being connected to said pull bar; a lihk-Lpi votally Connected atone end to the second end ofsaid lever fierce multiplying hydraulic Connecting meai-is having a driving piston of relatiVelysmaH diameteF and a'driven'piston of relati'vely large diameter; thejopposite end of said ling being connectedto: the driving piston of said'io'r'ce -'muitiplylng hydraulic connecting means the driven iston of s'aid forcemultiplying hydraulic connecting means": being connected to thesecond' end of saiddever: said drive means being-permeated 7 to said link between the ends thereof; said drive means mo'fingysaidlink about the=pivotbn its said opposite 'end'torotate said lever and move the clampinto engagement with the paper stack; 's"22id" drive means thereafter moving the opposite end or said-link about the pivotat'itsnrst mentioned endtol actuate said forts multiplyinghydraulic-means to move said clamp into pressure engagement with said paper steak. 7 V R 17. In; a paper cutting machine atablefor sup portinga paper stack to -be out} a clamp forcompressing the paperstacm saicl clamp' being mov able toward and away from, said pa'per stack; drive means-for said-clamp; said ,clarnp having a pull ban a pivotally-rineunted rlever;thefirst end of-said lever being oo'nnectedatosaid pull bar; a linkpivolhllyhhfiriected at onezencl to the second end of said lever; force multiplying hydraulic connectingmeans having a driviiigiplston of relatively small diameterandua driven piston of relatively large diameter; -:the-.:opposite end of said link being iconn'eeted 3130" :the driving r'piston "of said forte iniil'tiplyin'g ihydraulii: "connecting means? the drivenzzpisten' of zsaid: force multipl-ying -hydrauiicscconnecting means beihg connected-to ;th'e; second end-of saidxrlever;

"said drive means-i being-i connectedkto said link between" the: ends: thereof; 1-.- sa-idaidrivei 1 means movingssaid abouvthemivdt on its saidxon pcsite end to rotate said lever and move the clamp into engagement with the paper stack; said drive means thereafter moving the opposite end of said link about the pivot at its first mentioned end to actuate said force multiplying hydraulic means to move said clamp into pressure en agement with said paper stack; a cylinder for said driving piston; a cylinder for said driven piston; a connecting duct between said cylinders; a reservoir and a by-pass duct between said cylinders and said reservoir; means for closing said by-pass duct as said driving cylinder is moved in the driving direction.

18. In a paper cutting machine a table for supporting a paper stack to be cut; a clamp for compressing the paper stack; said clamp being movable toward and away from said paper stack; drive means for said clamp; said clamp having a pull bar; a pivotally mounted lever; the first end of said lever being connected to said pull bar; a link pivotally connected at one end to the second end of said lever; force multiplying hydraulic connecting means having a driving piston of relatively small diameter and a driven piston of relatively large diameter; the opposite end of said link being connected to the driving piston of said force multiplying hydraulic connecting means; the driven piston of said force multiplying hydraulic connecting means being connected to the second end of said lever; said drive means being connected to said link between the ends thereof; said drive means moving said link about the pivot on its said opposite end to rotate said lever and move the clamp into engagement with the paper stack; said drive means thereafter moving the opposite end of said link about the pivot at its first mentioned end to actuate said force multiplying hydraulic means to move said clamp into pressure engagement with said paper stack; a cylinder for said driving piston; a cylinder for said driven piston; a connecting duct between said cylinders; a reservoir and a by-pass duct connecting said cylinders and said reservoir; means for closing said by-pass duct as said driving cylinder is moved in the driving direction; an additional duct between the cylinder housing the driven piston and the reservoir; valve means between said cylinder and said additional duct controlling the maximum pressure in said cylinder.

19. In a paper cutting machine a table for supporting a paper stack to be cut; a clamp for compressing the paper stack; said clamp being movable toward and away from said paper stack; drive means for said clamp; said clamp having a pull bar; a pivotally mounted lever; the first end of said lever being connected to said pull bar; a link pivotally connected at one end to the second end of said lever force multiplying hydraulic connecting means having a driving piston of relatively small diameter and a driven piston of relatively large diameter; the opposite end of said link being connected to the driving piston of said force multiplying hydraulic connecting means; the driven piston of said force multiplying hydraulic connecting means being connected to the second end of said lever; said drive means being connected to said link between the ends thereof; said drive means moving said link about the pivot on its said opposite end to rotate said lever and move the clamp into engagement with the paper stock; said drive means thereafter moving the opposite end of said link about the pivot at its first mentioned end to actuate said force multiplying hydraulic means to move said clamp into pressure engagement with said paper stack; a cylinder for said driving piston; a cylinder for said driven piston; a connecting duct between said cylinders; a reservoir and a by-pass duct between said cylinders and said reservoir; a valve for closing said by-pass duct; said valve being operable to closed position on movement of said driving piston in the driving direction and being operable to open position on return movement of said driving piston.

20. A clamp for compressing a paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack; and means for controlling the clamp during its movement toward and away from said paper stack to avoid tilting of said clamp.

21. A clamp for compressing a paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and means for controlling the clamp during its movement toward and away from said paper stack to avoid tilting of said clamp; said means comprising a rotatable shaft parallel to said clamp; and a gear connection from opposite ends of said shaft to opposite ends of said clamp.

22. A clamp for compressing a paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp into contact with said paper stack; and means for controlling the clamp during its movement toward and away from said paper stack to avoid tilting of said clamp; said means comprising a rotatable shaft parallel to said clamp; a gear at each end of said shaft; a rack at each end of said clamp engaged by said gear, the torsional resistance of said shaft resisting uneven movement of the opposite ends of the clamp.

23. A clamp for compressing a paper stack; said clamp being movable toward and away from said paper stack; drive means; a first set of connections from said drive means to said clamp operable to move said clamp relatively rapidly into contact with said paper stack and additional force multiplying connections between said drive means and said clamp for forcing said clamp into high pressure engagement with said paper stack after said clamp has come into engagement with said paper stack; said first set of connections being connected to one side of said clamp; said additional force multiplying connections being connected to both sides of said clamp.

FREDERICK W. SEYBOLD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,880,598 Tyler et a1 Oct. 4, 1932 FOREIGN PATENTS Number Country Date 118,151 Australia Feb. 15, 1944 406,441 Great Britain Mar. 1, 1934 

